A Network Processor (NP) is an Application Specific Instruction Processor (ASIP) designed for network applications; the ASIP has its own structure characteristics and specialized circuit designs to apply to network packet processing; besides, it is a software programmable chip. The NP enables a network system to have high performance and flexibility.
The NP is applied to different situations. Types of table lookup, item capacities, sizes of item entry and requirements on table lookup performance have great difference, so the technical problems to be solved include the following two aspects:
1. the NP manages items, requiring seamless and faultless lookup under the condition of realizing a certain update performance. For the storage of an item with big single entry width, multiple memory addresses may be needed to store a single entry; so, in an item update process, it is especially important to ensure an atomic operation of the item; and
2. when the item is stored in an off-chip memory, due to the influence of its own structure, an access bandwidth in an item lookup process is also the problem to be solved.